The continuous depth space is discretized in order to define the set of \(D\)  bins used in the depth distributions \(\mathbf {D}\) . Depth discretization can be performed with uniform discretization (UD) with a fixed bin size, spacing-increasing discretization (SID) [1]} with increasing bin sizes in \(\log \)  space, or linear-increasing discretization (LID) [2]} with linearly increasing bin sizes. Depth discretization techniques are visualized in Figure REF .
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